X-ray tube.



E. GRIMES.

X-RAY TUBE.

APPLICATION FILED NOV- 19. 1913.

Patented May 23, 1916.

mmmmmmm WWW ELI GRIMES, OF DES MOINES, IOWA.

X-RAY TUBE.

Specification of Letters Patent.

Patented May 23, 1916.

Application filed November 19, 1913. Serial No. 801,778.

To all whom it may concern:

Be it known that I, ELI GRIMES, a citizen of the United States, residingat Des Moines, in the county of Polk and State of Iowa, have inventednew and useful Improvements in X-Ray Tubes, of which the following is aspecification.

The present invention relates to a vacuum or Crookes tube, such as areused for the generation of Roentgen or X-rays.

In working with X-ray tubes, the rays coming from one electrode arefocused on a target located near the middle of the tube where theyimpinge the target and X-rays are then emitted through the side of thetube. As a result of this actionthe rays, as they issue from the pointof fluorescence, diverge, which means that the tubes must be at certaindefinite distance from the object to be radiographed and in a certaindefinite angular position relative to the anode, in order that theradioactivity may be intense enough to give satisfactory results.

With the ordinary glasstube it is necessary to thus scatter the rays toprevent the heat of the rays from softening the glass and melting a spotat the focal point. The present invention aims to build the tube in sucha way that the cathode rays will not be fo.- cused on the anode, whichcauses the X-rays .to issue therefrom in a diverging current, but

the X-rays will leave the tube as parallel rays, thus giving a morenearly homogenous radiation from the point of fluorescence.

The invention also aims to eliminate the over-heating and concentrationof the rays at the focal point.

In general the invention mav be said to consist in building an X-raytube wherein the cathode rays are not focused upon a target, and theX-rays travel out from the tube in parallel and as a homogeneous streamof substantially radioactivity. In carrying out my invention one or moreof the electrodes is made of carbon, aluminum or some materialrelatively pervious to the rays so that the X-ray can pass through itand travel out in parallel lines without overheating the tube andwithout being scattered.

. In the accompanying drawings, Fi re 1 is a longitudinal sectionthrough an -ray tube embodying one form of my invention,

and Fi 2 is a vertical section through the same'tu e.

Reference now being had to the drawings, the numeral 1 indicates acylinder of the de-' sired length and diameter. Secured to one end ofthe cylinder, in any well known manner, is a plate of nickel copperindicated by the numeral 2 which serves as the anode and the oppositeend of the tube is provided with preferably a plate of thin carbon,indicated by the numeral 3, which serves as the cathode.

The tube .1 is exhausted, asis common with X-ray tubes of thischaracter, and any suitable means, as is common within the art may beemployed to retain the vacuum within the tube 1 to the proper degree ofexhaustion.

The thin carbon plate 3 is transparent to the X-rays which are of highlypenetrative power, thereby the rays of less penetrative power will beabsorbed within the carbon plate. The rays from the cathode electrode 3travel through the tube to the anode where they impinge upon the anodeand are then reflected back through the cathode 3 as parallel rays (asindicated by the arrows in the drawing) ofv highly penetrative power.From this it will be understood that the anode 2 is opaque andimpervious to the rays, and by sending the rays directly toward thecathode and not at an angle, as is common in tubes previouslyconstructed, the volume of parallel X-rays is much greater than otherX-rays which have been produced by directing the rays at an angle.

Whereas I have shown the anode and cathode at the ends of the tube, itis, of

course, to be understood that the electrodes may be formed within thetube or made an integral part thereof.

By the rays passing through the carbon electrode, there is nooverheating and there is no concentration of the rays at any point andit also results that the rays travel in parallel lines for a greatdistance, not being scattered or lost.

Instead of the nickel copper electrode. a thin aluminum disk pervious'toX-rays may be substituted therefor and opposite to the carbon electrode,so that the X-rays may travel outwardly through the aluminum plate thesame as they pass through the carbon plate or at least enough of the X-rays will go through the aluminum plate to impervious to X-rays and aflat electrode pervious to X-rays arranged parallel with the otherelectrode whereby parallel rays will be projected from the tube.

2. An X-ray apparatus comprising a tube having a fiat electrode perviousto the 'X-rays and arranged to transmit the QQ-rays emanating from theother electrode in [substantially parallel relation to one other andwlthout distortion.

3. An X-ray apparatus comprlsing 'a vacuum cylinder, an anode electrodecomprising nickel copper, an electrode comprising a thin carbonlatespaced from the first mentioned electro e and in parallel relationwhereby parallel X-rays may be projected from, the tube. a g

4. An X-ray tube, com'prisin a flat cathode pervious to X-rays and a atanode impervious to X-rays, whereby X-rays will be discharged throughthe cathode and emerge in a beam of parallel rays.

5. In apparatus of the class described, an X-ray tube comprising a'flatcathode transparent to X-rays, a flat anode parallel with said cathodeand in close proximity thereto.

In witness whereof, I hereunto subscribemy name to this specification inthe presence of two witnesses. ELI GRIMES.

Witnesses:

VERONICA STAPLETON, SARA B. COOPER.

